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Immunotherapy shown to be more effective than chemotherapy for treating bladder cancer

Immunotherapy increases survival time and quality of life in patients with advanced bladder cancer where initial cisplatin-based treatment is no longer effective.

An international multicentre study led by cancer specialist Joaquim Bellmunt, director of the Hospital del Mar Medical Research Institute (IMIM) and coordinator of the IMIM's Genitourinary Oncology research group, has demonstrated the effectiveness of immunotherapy in treating advanced bladder cancer when the initial chemotherapy using cisplatin no longer works. It is the first time patient survival has been significantly prolonged in this kind of situation.

The treatment also improves the quality of life of patients with respect to chemotherapy. This phase III study published in the highly prestigious New England Journal of Medicine, a benchmark for advances in applied medicine, becomes a reference work as until now there had been no significant breakthroughs in bladder cancer treatment that could be applied when the first option was no longer effective. These results provide evidence supporting the use of Pembrolizumab, an immunotherapy drug, as a new standard treatment for advanced bladder cancer, as has also been demonstrated for other types of tumour such as melanoma and lung cancer.

The study, coordinated from the Dana Farber Cancer Institute (DFCI) in Boston, involved a total of 542 patients from 29 countries, who were divided into two groups. The first set were given the immunotherapy drug Pembrolizumab, while the others took one of the three chemotherapeutics commonly used to treat these patients. “The results of the trial show that patients treated with immunotherapy using Pembrolizumab, had a greater overall survival rate, fewer side effects, and a better quality of life, in contrast to patients treated with chemotherapy. The median overall survival was 10.3 months with Pembrolizumab, and 7.4 months with chemotherapy", explains Dr. Joaquim Bellmunt.

In addition to increased survival, more patients responded to the immunotherapy, and continued to do so for longer, than those treated with chemotherapy. "The percentage of patients in whom the tumour showed either a size reduction or actually disappeared was nearly twice as high among those treated with immunotherapy: 21%, versus 11% for patients receiving chemotherapy”, explains Dr. Bellmunt. "Additionally, in patients treated with immunotherapy who respond to the treatment, we see that this benefit is maintained. While the average response to chemotherapy is only 4.3 months, this figure has still not been reached for immunotherapy treatment", continues Dr. Bellmunt.

The results of the study were so evident and immunotherapy proved so superior to chemotherapy, that the independent committee responsible for evaluating the intermediate results of the trial recommended ending it early in order to translate the results to clinical treatment as soon as possible.

More than twenty years of chemotherapy with no changes in advanced bladder cancer treatment

The treatment of choice or standard first-line therapy in patients suffering advanced or metastatic bladder cancer is still chemotherapy, in different combinations based on cisplatin. This treatment leads to a short average increased survival time of 12 to 15 months. When patients no longer responded to this first line of treatment and the disease continued to progress, until now there were few treatment options and no agent had been shown to significantly improve survival.

In the United States, the Food and Drug Administration (FDA) approved two immunotherapy drugs, based mainly on data from phase II studies (rate of response) as there was no alternative after platinum-based chemotherapy. Taxane treatment is also commonly used in these situations In contrast, Vinflunine was approved for use in Europe based on data from a phase III study, also led by Dr. Bellmunt, which achieved a response rate of 9%, and a 2-month increase in global survival.

Given that the average overall survival time for second line treatment is only 5-7 months, there was a need to be able to offer an effective therapeutic option for patients affected by advanced bladder carcinoma.

Immunotherapy, a fundamental tool in the restoration of the immune system allowing it to attack the tumour

Finally, this new therapeutic alternative comes from the gamut of immunotherapy treatments that restore or intensify the ability of the immune system to attack a tumour. These treatments have been proven to have favourable antitumoral activity and a good safety profile in many other advanced malignant tumours, which now include bladder cancer.

This was shown by preliminary data from a phase I study with Pembrolizumab, which was administered to a group of patients with advanced bladder carcinoma who could not take cisplatin as a standard treatment. The positive results from that work were used to propose this international phase III trial, an acclaimed multicentre study that has been recognised at a global level by the accredited publication, the New England Journal of Medicine. “The results provide support for Pembrolizumab and arguments for its use as the new treatment standard in cases of advanced bladder cancer", concludes Dr. Bellmunt.

This study will very soon become the basis for new studies into the treatment of bladder cancer. Work is already underway at Hospital del Mar on combination studies using Pembrolizumab to further enhance the results of advanced bladder cancer treatment.